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Diffstat (limited to 'debian/xsfbs/xsfbs.sh')
| -rw-r--r-- | debian/xsfbs/xsfbs.sh | 853 |
1 files changed, 853 insertions, 0 deletions
diff --git a/debian/xsfbs/xsfbs.sh b/debian/xsfbs/xsfbs.sh new file mode 100644 index 0000000..781826f --- /dev/null +++ b/debian/xsfbs/xsfbs.sh @@ -0,0 +1,853 @@ +# $Id$ + +# This is the X Strike Force shell library for X Window System package +# maintainer scripts. It serves to define shell functions commonly used by +# such packages, and performs some error checking necessary for proper operation +# of those functions. By itself, it does not "do" much; the maintainer scripts +# invoke the functions defined here to accomplish package installation and +# removal tasks. + +# If you are reading this within a Debian package maintainer script (e.g., +# /var/lib/dpkg)info/PACKAGE.{config,preinst,postinst,prerm,postrm}), you can +# skip past this library by scanning forward in this file to the string +# "GOBSTOPPER". + +SOURCE_VERSION=@SOURCE_VERSION@ +OFFICIAL_BUILD=@OFFICIAL_BUILD@ + +# Use special abnormal exit codes so that problems with this library are more +# easily tracked down. +SHELL_LIB_INTERNAL_ERROR=86 +SHELL_LIB_THROWN_ERROR=74 +SHELL_LIB_USAGE_ERROR=99 + +# old -> new variable names +if [ -z "$DEBUG_XORG_PACKAGE" ] && [ -n "$DEBUG_XFREE86_PACKAGE" ]; then + DEBUG_XORG_PACKAGE="$DEBUG_XFREE86_PACKAGE" +fi +if [ -z "$DEBUG_XORG_DEBCONF" ] && [ -n "$DEBUG_XFREE86_DEBCONF" ]; then + DEBUG_XORG_DEBCONF="$DEBUG_XFREE86_DEBCONF" +fi + +# initial sanity checks +if [ -z "$THIS_PACKAGE" ]; then + cat >&2 <<EOF +Error: package maintainer script attempted to use shell library without +definining \$THIS_PACKAGE shell variable. Please report the package name, +version, and the text of this error message to the Debian Bug Tracking System. +Visit <http://www.debian.org/Bugs/Reporting> on the World Wide Web for +instructions, read the file /usr/share/doc/debian/bug-reporting.txt from the +"doc-debian" package, or install the "reportbug" package and use the command of +the same name to file a report against version $SOURCE_VERSION of this package. +EOF + exit $SHELL_LIB_USAGE_ERROR +fi + +if [ -z "$THIS_SCRIPT" ]; then + cat >&2 <<EOF +Error: package maintainer script attempted to use shell library without +definining \$THIS_SCRIPT shell variable. Please report the package name, +version, and the text of this error message to the Debian Bug Tracking System. +Visit <http://www.debian.org/Bugs/Reporting> on the World Wide Web for +instructions, read the file /usr/share/doc/debian/bug-reporting.txt from the +"doc-debian" package, or install the "reportbug" package and use the command of +the same name to file a report against version $SOURCE_VERSION of the +"$THIS_PACKAGE" package. +EOF + exit $SHELL_LIB_USAGE_ERROR +fi + +if [ "$1" = "reconfigure" ] || [ -n "$DEBCONF_RECONFIGURE" ]; then + RECONFIGURE="true" +else + RECONFIGURE= +fi + +if ([ "$1" = "install" ] || [ "$1" = "configure" ]) && [ -z "$2" ]; then + FIRSTINST="yes" +fi + +if [ -z "$RECONFIGURE" ] && [ -z "$FIRSTINST" ]; then + UPGRADE="yes" +fi + +trap "message;\ + message \"Received signal. Aborting $THIS_PACKAGE package $THIS_SCRIPT script.\";\ + message;\ + exit 1" HUP INT QUIT TERM + +reject_nondigits () { + # syntax: reject_nondigits [ operand ... ] + # + # scan operands (typically shell variables whose values cannot be trusted) for + # characters other than decimal digits and barf if any are found + while [ -n "$1" ]; do + # does the operand contain anything but digits? + if ! expr "$1" : "[[:digit:]]\+$" > /dev/null 2>&1; then + # can't use die(), because it wraps message() which wraps this function + echo "$THIS_PACKAGE $THIS_SCRIPT error: reject_nondigits() encountered" \ + "possibly malicious garbage \"$1\"" >&2 + exit $SHELL_LIB_THROWN_ERROR + fi + shift + done +} + +reject_whitespace () { + # syntax: reject_whitespace [ operand ] + # + # scan operand (typically a shell variable whose value cannot be trusted) for + # whitespace characters and barf if any are found + if [ -n "$1" ]; then + # does the operand contain any whitespace? + if expr "$1" : "[[:space:]]" > /dev/null 2>&1; then + # can't use die(), because I want to avoid forward references + echo "$THIS_PACKAGE $THIS_SCRIPT error: reject_whitespace() encountered" \ + "possibly malicious garbage \"$1\"" >&2 + exit $SHELL_LIB_THROWN_ERROR + fi + fi +} + +reject_unlikely_path_chars () { + # syntax: reject_unlikely_path_chars [ operand ... ] + # + # scan operands (typically shell variables whose values cannot be trusted) for + # characters unlikely to be seen in a path and which the shell might + # interpret and barf if any are found + while [ -n "$1" ]; do + # does the operand contain any funny characters? + if expr "$1" : '.*[!$&()*;<>?|].*' > /dev/null 2>&1; then + # can't use die(), because I want to avoid forward references + echo "$THIS_PACKAGE $THIS_SCRIPT error: reject_unlikely_path_chars()" \ + "encountered possibly malicious garbage \"$1\"" >&2 + exit $SHELL_LIB_THROWN_ERROR + fi + shift + done +} + +# Query the terminal to establish a default number of columns to use for +# displaying messages to the user. This is used only as a fallback in the +# event the COLUMNS variable is not set. ($COLUMNS can react to SIGWINCH while +# the script is running, and this cannot, only being calculated once.) +DEFCOLUMNS=$(stty size 2> /dev/null | awk '{print $2}') || true +if ! expr "$DEFCOLUMNS" : "[[:digit:]]\+$" > /dev/null 2>&1; then + DEFCOLUMNS=80 +fi + +message () { + # pretty-print messages of arbitrary length + reject_nondigits "$COLUMNS" + echo "$*" | fmt -t -w ${COLUMNS:-$DEFCOLUMNS} >&2 +} + +observe () { + # syntax: observe message ... + # + # issue observational message suitable for logging someday when support for + # it exists in dpkg + if [ -n "$DEBUG_XORG_PACKAGE" ]; then + message "$THIS_PACKAGE $THIS_SCRIPT note: $*" + fi +} + +warn () { + # syntax: warn message ... + # + # issue warning message suitable for logging someday when support for + # it exists in dpkg; also send to standard error + message "$THIS_PACKAGE $THIS_SCRIPT warning: $*" +} + +die () { + # syntax: die message ... + # + # exit script with error message + message "$THIS_PACKAGE $THIS_SCRIPT error: $*" + exit $SHELL_LIB_THROWN_ERROR +} + +internal_error () { + # exit script with error; essentially a "THIS SHOULD NEVER HAPPEN" message + message "internal error: $*" + if [ -n "$OFFICIAL_BUILD" ]; then + message "Please report a bug in the $THIS_SCRIPT script of the" \ + "$THIS_PACKAGE package, version $SOURCE_VERSION to the Debian Bug" \ + "Tracking System. Include all messages above that mention the" \ + "$THIS_PACKAGE package. Visit " \ + "<http://www.debian.org/Bugs/Reporting> on the World Wide Web for" \ + "instructions, read the file" \ + "/usr/share/doc/debian/bug-reporting.txt from the doc-debian" \ + "package, or install the reportbug package and use the command of" \ + "the same name to file a report." + fi + exit $SHELL_LIB_INTERNAL_ERROR +} + +usage_error () { + message "usage error: $*" + message "Please report a bug in the $THIS_SCRIPT script of the" \ + "$THIS_PACKAGE package, version $SOURCE_VERSION to the Debian Bug" \ + "Tracking System. Include all messages above that mention the" \ + "$THIS_PACKAGE package. Visit " \ + "<http://www.debian.org/Bugs/Reporting> on the World Wide Web for" \ + "instructions, read the file" \ + "/usr/share/doc/debian/bug-reporting.txt from the doc-debian" \ + "package, or install the reportbug package and use the command of" \ + "the same name to file a report." + exit $SHELL_LIB_USAGE_ERROR +} + + +maplink () { + # returns what symlink should point to; i.e., what the "sane" answer is + # Keep this in sync with the debian/*.links files. + # This is only needed for symlinks to directories. + # + # XXX: Most of these look wrong in the X11R7 world and need to be fixed. + # If we've stopped using this function, fixing it might enable us to re-enable + # it again and catch more errors. + case "$1" in + /etc/X11/xkb/compiled) echo /var/lib/xkb ;; + /etc/X11/xkb/xkbcomp) echo /usr/X11R6/bin/xkbcomp ;; + /usr/X11R6/lib/X11/app-defaults) echo /etc/X11/app-defaults ;; + /usr/X11R6/lib/X11/fs) echo /etc/X11/fs ;; + /usr/X11R6/lib/X11/lbxproxy) echo /etc/X11/lbxproxy ;; + /usr/X11R6/lib/X11/proxymngr) echo /etc/X11/proxymngr ;; + /usr/X11R6/lib/X11/rstart) echo /etc/X11/rstart ;; + /usr/X11R6/lib/X11/twm) echo /etc/X11/twm ;; + /usr/X11R6/lib/X11/xdm) echo /etc/X11/xdm ;; + /usr/X11R6/lib/X11/xinit) echo /etc/X11/xinit ;; + /usr/X11R6/lib/X11/xkb) echo /etc/X11/xkb ;; + /usr/X11R6/lib/X11/xserver) echo /etc/X11/xserver ;; + /usr/X11R6/lib/X11/xsm) echo /etc/X11/xsm ;; + /usr/bin/X11) echo ../X11R6/bin ;; + /usr/bin/rstartd) echo ../X11R6/bin/rstartd ;; + /usr/include/X11) echo ../X11R6/include/X11 ;; + /usr/lib/X11) echo ../X11R6/lib/X11 ;; + *) internal_error "maplink() called with unknown path \"$1\"" ;; + esac +} + +analyze_path () { + # given a supplied set of pathnames, break each one up by directory and do an + # ls -dl on each component, cumulatively; i.e. + # analyze_path /usr/X11R6/bin -> ls -dl /usr /usr/X11R6 /usr/X11R6/bin + # Thanks to Randolph Chung for this clever hack. + + local f g + + while [ -n "$1" ]; do + reject_whitespace "$1" + g= + message "Analyzing $1:" + for f in $(echo "$1" | tr / \ ); do + if [ -e /$g$f ]; then + ls -dl /$g$f /$g$f.dpkg-* 2> /dev/null || true + g=$g$f/ + else + message "/$g$f: nonexistent; directory contents of /$g:" + ls -l /$g + break + fi + done + shift + done +} + +find_culprits () { + local f p dpkg_info_dir possible_culprits smoking_guns bad_packages package \ + msg + + reject_whitespace "$1" + message "Searching for overlapping packages..." + dpkg_info_dir=/var/lib/dpkg/info + if [ -d $dpkg_info_dir ]; then + if [ "$(echo $dpkg_info_dir/*.list)" != "$dpkg_info_dir/*.list" ]; then + possible_culprits=$(ls -1 $dpkg_info_dir/*.list | egrep -v \ + "(xbase-clients|x11-common|xfs|xlibs)") + if [ -n "$possible_culprits" ]; then + smoking_guns=$(grep -l "$1" $possible_culprits || true) + if [ -n "$smoking_guns" ]; then + bad_packages=$(printf "\\n") + for f in $smoking_guns; do + # too bad you can't nest parameter expansion voodoo + p=${f%*.list} # strip off the trailing ".list" + package=${p##*/} # strip off the directories + bad_packages=$(printf "%s\n%s" "$bad_packages" "$package") + done + msg=$(cat <<EOF +The following packages appear to have file overlaps with the X.Org packages; +these packages are either very old, or in violation of Debian Policy. Try +upgrading each of these packages to the latest available version if possible: +for example, with the command "apt-get install". If no newer version of a +package is available, you will have to remove it; for example, with the command +"apt-get remove". If even the latest available version of the package has +this file overlap, please file a bug against that package with the Debian Bug +Tracking System. You may want to refer the package maintainer to section 12.8 +of the Debian Policy manual. +EOF +) + message "$msg" + message "The overlapping packages are: $bad_packages" + else + message "no overlaps found." + fi + fi + else + message "cannot search; no matches for $dpkg_info_dir/*.list." + fi + else + message "cannot search; $dpkg_info_dir does not exist." + fi +} + +check_symlink () { + # syntax: check_symlink symlink + # + # See if specified symlink points where it is supposed to. Return 0 if it + # does, and 1 if it does not. + # + # Primarily used by check_symlinks_and_warn() and check_symlinks_and_bomb(). + + local symlink + + # validate arguments + if [ $# -ne 1 ]; then + usage_error "check_symlink() called with wrong number of arguments;" \ + "expected 1, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + symlink="$1" + + if [ "$(maplink "$symlink")" = "$(readlink "$symlink")" ]; then + return 0 + else + return 1 + fi +} + +check_symlinks_and_warn () { + # syntax: check_symlinks_and_warn symlink ... + # + # For each argument, check for symlink sanity, and warn if it isn't sane. + # + # Call this function from a preinst script in the event $1 is "upgrade" or + # "install". + + local errmsg symlink + + # validate arguments + if [ $# -lt 1 ]; then + usage_error "check_symlinks_and_warn() called with wrong number of" \ + "arguments; expected at least 1, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + while [ -n "$1" ]; do + symlink="$1" + if [ -L "$symlink" ]; then + if ! check_symlink "$symlink"; then + observe "$symlink symbolic link points to wrong location" \ + "$(readlink "$symlink"); removing" + rm "$symlink" + fi + elif [ -e "$symlink" ]; then + errmsg="$symlink exists and is not a symbolic link; this package cannot" + errmsg="$errmsg be installed until this" + if [ -f "$symlink" ]; then + errmsg="$errmsg file" + elif [ -d "$symlink" ]; then + errmsg="$errmsg directory" + else + errmsg="$errmsg thing" + fi + errmsg="$errmsg is removed" + die "$errmsg" + fi + shift + done +} + +check_symlinks_and_bomb () { + # syntax: check_symlinks_and_bomb symlink ... + # + # For each argument, check for symlink sanity, and bomb if it isn't sane. + # + # Call this function from a postinst script. + + local problem symlink + + # validate arguments + if [ $# -lt 1 ]; then + usage_error "check_symlinks_and_bomb() called with wrong number of" + "arguments; expected at least 1, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + while [ -n "$1" ]; do + problem= + symlink="$1" + if [ -L "$symlink" ]; then + if ! check_symlink "$symlink"; then + problem=yes + warn "$symlink symbolic link points to wrong location" \ + "$(readlink "$symlink")" + fi + elif [ -e "$symlink" ]; then + problem=yes + warn "$symlink is not a symbolic link" + else + problem=yes + warn "$symlink symbolic link does not exist" + fi + if [ -n "$problem" ]; then + analyze_path "$symlink" "$(readlink "$symlink")" + find_culprits "$symlink" + die "bad symbolic links on system" + fi + shift + done +} + +font_update () { + # run $UPDATECMDS in $FONTDIRS + + local dir cmd shortcmd x_font_dir_prefix + + x_font_dir_prefix="/usr/share/fonts/X11" + + if [ -z "$UPDATECMDS" ]; then + usage_error "font_update() called but \$UPDATECMDS not set" + fi + if [ -z "$FONTDIRS" ]; then + usage_error "font_update() called but \$FONTDIRS not set" + fi + + reject_unlikely_path_chars "$UPDATECMDS" + reject_unlikely_path_chars "$FONTDIRS" + + for dir in $FONTDIRS; do + if [ -d "$x_font_dir_prefix/$dir" ]; then + for cmd in $UPDATECMDS; do + if which "$cmd" > /dev/null 2>&1; then + shortcmd=${cmd##*/} + observe "running $shortcmd in $dir font directory" + cmd_opts= + if [ "$shortcmd" = "update-fonts-alias" ]; then + cmd_opts=--x11r7-layout + fi + if [ "$shortcmd" = "update-fonts-dir" ]; then + cmd_opts=--x11r7-layout + fi + if [ "$shortcmd" = "update-fonts-scale" ]; then + cmd_opts=--x11r7-layout + fi + $cmd $cmd_opts $dir || warn "$cmd $cmd_opts $dir" \ + "failed; font directory data may not" \ + "be up to date" + else + warn "$cmd not found; not updating corresponding $dir font" \ + "directory data" + fi + done + else + warn "$dir is not a directory; not updating font directory data" + fi + done +} + +remove_conffile_prepare () { + # syntax: remove_conffile_prepare filename official_md5sum ... + # + # Check a conffile "filename" against a list of canonical MD5 checksums. + # If the file's current MD5 checksum matches one of the "official_md5sum" + # operands provided, then prepare the conffile for removal from the system. + # We defer actual deletion until the package is configured so that we can + # roll this operation back if package installation fails. + # + # Call this function from a preinst script in the event $1 is "upgrade" or + # "install" and verify $2 to ensure the package is being upgraded from a + # version (or installed over a version removed-but-not-purged) prior to the + # one in which the conffile was obsoleted. + + local conffile current_checksum + + # validate arguments + if [ $# -lt 2 ]; then + usage_error "remove_conffile_prepare() called with wrong number of" \ + "arguments; expected at least 2, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + conffile="$1" + shift + + # does the conffile even exist? + if [ -e "$conffile" ]; then + # calculate its checksum + current_checksum=$(md5sum < "$conffile" | sed 's/[[:space:]].*//') + # compare it to each supplied checksum + while [ -n "$1" ]; do + if [ "$current_checksum" = "$1" ]; then + # we found a match; move the confffile and stop looking + observe "preparing obsolete conffile $conffile for removal" + mv "$conffile" "$conffile.$THIS_PACKAGE-tmp" + break + fi + shift + done + fi +} + +remove_conffile_lookup () { + # syntax: remove_conffile_lookup package filename + # + # Lookup the md5sum of a conffile in dpkg's database, and prepare for removal + # if it matches the actual file's md5sum. + # + # Call this function when you would call remove_conffile_prepare but only + # want to check against dpkg's status database instead of known checksums. + + local package conffile old_md5sum + + # validate arguments + if [ $# -ne 2 ]; then + usage_error "remove_conffile_lookup() called with wrong number of" \ + "arguments; expected 1, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + package="$1" + conffile="$2" + + if ! [ -e "$conffile" ]; then + return + fi + old_md5sum="$(dpkg-query -W -f='${Conffiles}' "$package" | \ + awk '{ if (match($0, "^ '"$conffile"' ")) print $2}')" + if [ -n "$old_md5sum" ]; then + remove_conffile_prepare "$conffile" "$old_md5sum" + fi +} + +remove_conffile_commit () { + # syntax: remove_conffile_commit filename + # + # Complete the removal of a conffile "filename" that has become obsolete. + # + # Call this function from a postinst script after having used + # remove_conffile_prepare() in the preinst. + + local conffile + + # validate arguments + if [ $# -ne 1 ]; then + usage_error "remove_conffile_commit() called with wrong number of" \ + "arguments; expected 1, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + conffile="$1" + + # if the temporary file created by remove_conffile_prepare() exists, remove it + if [ -e "$conffile.$THIS_PACKAGE-tmp" ]; then + observe "committing removal of obsolete conffile $conffile" + rm "$conffile.$THIS_PACKAGE-tmp" + fi +} + +remove_conffile_rollback () { + # syntax: remove_conffile_rollback filename + # + # Roll back the removal of a conffile "filename". + # + # Call this function from a postrm script in the event $1 is "abort-upgrade" + # or "abort-install" is after having used remove_conffile_prepare() in the + # preinst. + + local conffile + + # validate arguments + if [ $# -ne 1 ]; then + usage_error "remove_conffile_rollback() called with wrong number of" \ + "arguments; expected 1, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + conffile="$1" + + # if the temporary file created by remove_conffile_prepare() exists, move it + # back + if [ -e "$conffile.$THIS_PACKAGE-tmp" ]; then + observe "rolling back removal of obsolete conffile $conffile" + mv "$conffile.$THIS_PACKAGE-tmp" "$conffile" + fi +} + +replace_conffile_with_symlink_prepare () { + # syntax: replace_conffile_with_symlink_prepare oldfilename newfilename \ + # official_md5sum ... + # + # Check a conffile "oldfilename" against a list of canonical MD5 checksums. + # If the file's current MD5 checksum matches one of the "official_md5sum" + # operands provided, then prepare the conffile for removal from the system. + # We defer actual deletion until the package is configured so that we can + # roll this operation back if package installation fails. Otherwise copy it + # to newfilename and let dpkg handle it through conffiles mechanism. + # + # Call this function from a preinst script in the event $1 is "upgrade" or + # "install" and verify $2 to ensure the package is being upgraded from a + # version (or installed over a version removed-but-not-purged) prior to the + # one in which the conffile was obsoleted. + + local conffile current_checksum + + # validate arguments + if [ $# -lt 3 ]; then + usage_error "replace_conffile_with_symlink_prepare() called with wrong" \ + " number of arguments; expected at least 3, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + oldconffile="$1" + shift + newconffile="$1" + shift + + remove_conffile_prepare "$_oldconffile" "$@" + # If $oldconffile still exists, then md5sums didn't match. + # Copy it to new one. + if [ -f "$oldconffile" ]; then + cp "$oldconffile" "$newconffile" + fi + +} + +replace_conffile_with_symlink_commit () { + # syntax: replace_conffile_with_symlink_commit oldfilename + # + # Complete the removal of a conffile "oldfilename" that has been + # replaced by a symlink. + # + # Call this function from a postinst script after having used + # replace_conffile_with_symlink_prepare() in the preinst. + + local conffile + + # validate arguments + if [ $# -ne 1 ]; then + usage_error "replace_conffile_with_symlink_commit() called with wrong" \ + "number of arguments; expected 1, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + conffile="$1" + + remove_conffile_commit "$conffile" +} + +replace_conffile_with_symlink_rollback () { + # syntax: replace_conffile_with_symlink_rollback oldfilename newfilename + # + # Roll back the replacing of a conffile "oldfilename" with symlink to + # "newfilename". + # + # Call this function from a postrm script in the event $1 is "abort-upgrade" + # or "abort-install" and verify $2 to ensure the package failed to upgrade + # from a version (or install over a version removed-but-not-purged) prior + # to the one in which the conffile was obsoleted. + # You should have used replace_conffile_with_symlink_prepare() in the + # preinst. + + local conffile + + # validate arguments + if [ $# -ne 2 ]; then + usage_error "replace_conffile_with_symlink_rollback() called with wrong" \ + "number of arguments; expected 2, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + oldconffile="$1" + newconffile="$2" + + remove_conffile_rollback "$_oldconffile" + if [ -f "$newconffile" ]; then + rm "$newconffile" + fi +} + +run () { + # syntax: run command [ argument ... ] + # + # Run specified command with optional arguments and report its exit status. + # Useful for commands whose exit status may be nonzero, but still acceptable, + # or commands whose failure is not fatal to us. + # + # NOTE: Do *not* use this function with db_get or db_metaget commands; in + # those cases the return value of the debconf command *must* be checked + # before the string returned by debconf is used for anything. + + local retval + + # validate arguments + if [ $# -lt 1 ]; then + usage_error "run() called with wrong number of arguments; expected at" \ + "least 1, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + "$@" || retval=$? + + if [ ${retval:-0} -ne 0 ]; then + observe "command \"$*\" exited with status $retval" + fi +} + +make_symlink_sane () { + # syntax: make_symlink_sane symlink target + # + # Ensure that the symbolic link symlink exists, and points to target. + # + # If symlink does not exist, create it and point it at target. + # + # If symlink exists but is not a symbolic link, back it up. + # + # If symlink exists, is a symbolic link, but points to the wrong location, fix + # it. + # + # If symlink exists, is a symbolic link, and already points to target, do + # nothing. + # + # This function wouldn't be needed if ln had an -I, --idempotent option. + + # Validate arguments. + if [ $# -ne 2 ]; then + usage_error "make_symlink_sane() called with wrong number of arguments;" \ + "expected 2, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + # We could just use the positional parameters as-is, but that makes things + # harder to follow. + local symlink target + + symlink="$1" + target="$2" + + if [ -L "$symlink" ] && [ "$(readlink "$symlink")" = "$target" ]; then + observe "link from $symlink to $target already exists" + else + observe "creating symbolic link from $symlink to $target" + mkdir -p "${target%/*}" "${symlink%/*}" + ln -s -b -S ".dpkg-old" "$target" "$symlink" + fi +} + +migrate_dir_to_symlink () { + # syntax: migrate_dir_to_symlink old_location new_location + # + # Per Debian Policy section 6.5.4, "A directory will never be replaced by a + # symbolic link to a directory or vice versa; instead, the existing state + # (symlink or not) will be left alone and dpkg will follow the symlink if + # there is one." + # + # We have to do it ourselves. + # + # This function moves the contents of old_location, a directory, into + # new_location, a directory, then makes old_location a symbolic link to + # new_location. + # + # old_location need not exist, but if it does, it must be a directory (or a + # symlink to a directory). If it is not, it is backed up. If new_location + # exists already and is not a directory, it is backed up. + # + # This function should be called from a package's preinst so that other + # packages unpacked after this one --- but before this package's postinst runs + # --- are unpacked into new_location even if their payloads contain + # old_location filespecs. + + # Validate arguments. + if [ $# -ne 2 ]; then + usage_error "migrate_dir_to_symlink() called with wrong number of" + "arguments; expected 2, got $#" + exit $SHELL_LIB_USAGE_ERROR + fi + + # We could just use the positional parameters as-is, but that makes things + # harder to follow. + local new old + + old="$1" + new="$2" + + # Is old location a symlink? + if [ -L "$old" ]; then + # Does it already point to new location? + if [ "$(readlink "$old")" = "$new" ]; then + # Nothing to do; migration has already been done. + observe "migration of $old to $new already done" + return 0 + else + # Back it up. + warn "backing up symbolic link $old as $old.dpkg-old" + mv -b "$old" "$old.dpkg-old" + fi + fi + + # Does old location exist, but is not a directory? + if [ -e "$old" ] && ! [ -d "$old" ]; then + # Back it up. + warn "backing up non-directory $old as $old.dpkg-old" + mv -b "$old" "$old.dpkg-old" + fi + + observe "migrating $old to $new" + + # Is new location a symlink? + if [ -L "$new" ]; then + # Does it point the wrong way, i.e., back to where we're migrating from? + if [ "$(readlink "$new")" = "$old" ]; then + # Get rid of it. + observe "removing symbolic link $new which points to $old" + rm "$new" + else + # Back it up. + warn "backing up symbolic link $new as $new.dpkg-old" + mv -b "$new" "$new.dpkg-old" + fi + fi + + # Does new location exist, but is not a directory? + if [ -e "$new" ] && ! [ -d "$new" ]; then + warn "backing up non-directory $new as $new.dpkg-old" + mv -b "$new" "$new.dpkg-old" + fi + + # Create new directory if it does not yet exist. + if ! [ -e "$new" ]; then + observe "creating $new" + mkdir -p "$new" + fi + + # Copy files in old location to new location. Back up any filenames that + # already exist in the new location with the extension ".dpkg-old". + observe "copying files from $old to $new" + if ! (cd "$old" && cp -a -b -S ".dpkg-old" . "$new"); then + die "error(s) encountered while copying files from $old to $new" + fi + + # Remove files at old location. + observe "removing $old" + rm -r "$old" + + # Create symlink from old location to new location. + make_symlink_sane "$old" "$new" +} + +# vim:set ai et sw=2 ts=2 tw=80: + +# GOBSTOPPER: The X Strike Force shell library ends here. |